Sorry man. Been busy and had to put it off for a while but you should have 3 wires from the tach as well as 2 for the light.
The green is the tach input wire and needs to be wired into the tach output behind the dash (or to an ignition box like the MSD box I have, there is a tach output built in)
red wire and black wire are power and ground. Power wire can be tapped into any power source behind the dash,a lot of guys use the rear defroster switch. And the ground is pretty simple. For the light? I would wire it into the foglight switch (if it's a gt), or into the headlight switch otherwise. As you'll want the tach light to come on with the other dash lights. Ground for the light can use the same ground as the tach.
That's all based off memory, but it should be close to accurate
The green is the tach input wire and needs to be wired into the tach output behind the dash (or to an ignition box like the MSD box I have, there is a tach output built in)
red wire and black wire are power and ground. Power wire can be tapped into any power source behind the dash,a lot of guys use the rear defroster switch. And the ground is pretty simple. For the light? I would wire it into the foglight switch (if it's a gt), or into the headlight switch otherwise. As you'll want the tach light to come on with the other dash lights. Ground for the light can use the same ground as the tach.
That's all based off memory, but it should be close to accurate